Ca45 ions uptake and efflux will be compared in normal and transformed confluent HE cells, as will Rb86 ion. Both monolayers and cell suspensions will be studied. The cell potential and relative ionic conductances will be measured using lipid permeable cations and merocyanine dyes. BIBLIOGRAPHIC REFERENCES: Characterization of gastric mucosal membranes. VIII. The localization of peptides by iodination and phosphorylation. Saccomani G., Shah, G., Spenney, J.G., Sachs, G.J. Biol. Chem. 250, 4802-4809, 1975. Kinne, R., Murer, H., Kinne-Saffran, E., Thees, M., Sachs, G: Sugar transport by renal plasma membrane vesicles. J. Membr. Biol. 21, 375-395, 1975.